Investing in the Time of Historic Highs

Is it time to bet against this rally? Are E-Trade and Baidu cheap enough to buy?

U.S. stocks advanced Thursday, marking the Dow Jones Industrial Average's 10th straight daily gain and another new closing all-time high. The last time the Dow 30 had that many up days in a row was in November 1996, a few weeks before former Fed Chairman Alan Greenspan made his famous remarks about the market's possible "irrational exuberance" during an otherwise bland speech.